Atazanavir



Better Known as: Reyataz

 * Marketed By: Bristol-Myers Squibb


 * Major Indication: Human Immunodeficiency Virus Infection


 * Drug Class: HIV Protease Inhibitor
 * Date of FDA Approval (Patent Expiration): 2003 (2018)


 * 2009 Sales: $1.2 Billion
 * Importance: It is the first HIV Protease inhibitor approved for once-daily dosing and also appears to have a reduced side-effect profile.
 * See Pharmaceutical Drugs for more information about other drugs and disorders.

Mechanism of Action
When HIV infects a host, it directs the synthesis of several polyproteins. The maturation of the virus to its infectious form requires that these polyproteins be cleaved to their component proteins by HIV Protease. The subunits of HIV Protease come together to form a catalytic tunnel capable of binding the nascent peptides and cleaving them into their mature form. Within this tunnel lies two Asp-Thr-Gly conserved sequences, which contain the catalytic Asp residues. These catalytic Asp residues carry out the hydrolytic cleavage of the polyprotein. Atazanavir binds with great specificity to these conserved sequences within the HIV Protease tunnel, preventing the nascent polyproteins from entering. Unable to actively cleave the nascent proteins into their appropriate form, HIV is unable to mature and proliferate, allowing the patients immune system to fight off the infection more easily.

Drug Resistance
The biggest difficulty with treating HIV is the rapidity at which it mutates and becomes resistant to treatments. To view a comprehensive and interactive analysis of the mutations which confer drug resistance to HIV Protease, See: HIV Protease Inhibitor Resistance Profile